Video Experimental Relacionado
Updated: Jul 16, 2026

10:59
Analysis of Translation Initiation During Stress Conditions by Polysome Profiling
Published on: May 19, 2014
Factor de iniciación traslacional y asociación ribosómica con la fracción de marco citoesquelético de las células
Cell
|May 1, 1984
Resumen
La asociación citoesquelética de los ribosomas y los factores de síntesis de proteínas en las células eucariotas es crucial para la regulación. Los tratamientos que liberan ribosomas del citoesqueleto también liberan factores de iniciación, destacando sus roles vinculados.
Área de la Ciencia:
- Biología celular Biología celular.
- Biología Molecular Biología Molecular
- La bioquímica es la bioquímica.
Sus antecedentes:
- El citoesqueleto juega un papel en la síntesis de proteínas y su regulación en las células eucariotas.
- Es esencial comprender la localización precisa y las interacciones del ARNm, los ribosomas y los factores asociados con el citoesqueleto.
Objetivo del estudio:
- Investigar la asociación de los ribosomas y los factores de iniciación de la síntesis de proteínas con el marco citoesquelético en las células HeLa.
- Determinar cómo varios tratamientos celulares afectan estas asociaciones y sus implicaciones para la síntesis de proteínas.
Principales métodos:
- Las células HeLa se fraccionaron en componentes solubles y citoesqueléticos a través de la lisis detergente y la centrifugación.
- Los ribosomas y los factores de iniciación específicos (eIF-2, eIF-3, eIF-4A, eIF-4B) se cuantificaron mediante inmunoblotación.
- Se analizaron los efectos del choque térmico, el fluoruro, la pactamicina, la citocalasina, el EDTA y la ribonucleasa en las fracciones celulares.
Principales resultados:
- Se encontró que los polisomas estaban preferentemente asociados con la fracción citoesquelética.
- Los factores de iniciación (eIF-2, eIF-3, eIF-4A, eIF-4B) se enriquecieron en la fracción citoesquelética en comparación con la fracción soluble.
- El choque térmico, el fluoruro, la pactamicina y la citocalasina indujeron la liberación tanto de ribosomas como de factores de iniciación en la fracción soluble.
Conclusiones:
- La asociación del factor de iniciación con el citoesqueleto se correlaciona con la presencia de ribosomas.
- La asociación del ribosoma con el citoesqueleto no requiere necesariamente un ARNm intacto.
- El citoesqueleto es parte integral de la regulación de la síntesis de proteínas mediante el anclaje de los ribosomas y los factores de iniciación.
Videos de Conceptos Relacionados
Improving Translational Accuracy
Base complementarity between the three base pairs of mRNA codon and the tRNA anticodon is not a failsafe mechanism. Inaccuracies can range from a single mismatch to no correct base pairing at all. The free energy difference between the correct and nearly correct base pairs can be as small as 3 kcal/ mol. With complementarity being the only proofreading step, the estimated error frequency would be one wrong amino acid in every 100 amino acids incorporated. However, error frequencies observed in...
Initiation of Translation
Initiating translation is complex because it involves multiple molecules. Initiator tRNA, ribosomal subunits, and eukaryotic initiation factors (eIFs) are all required to assemble on the initiation codon of mRNA. This process consists of several steps that are mediated by different eIFs.
First, the initiator tRNA must be selected from the pool of elongator tRNAs by eukaryotic initiation factor 2 (eIF2). The initiator tRNA (Met-tRNAi) has conserved sequence elements including modified bases at...
First, the initiator tRNA must be selected from the pool of elongator tRNAs by eukaryotic initiation factor 2 (eIF2). The initiator tRNA (Met-tRNAi) has conserved sequence elements including modified bases at...
Cotranslational Protein Translocation
Translocation of proteins across membranes is an ancient process that occurs even in bacteria and archaebacteria. In fact, the components of the translocation machinery are still conserved between prokaryotes and eukaryotes.
Sec61 channel partners for cotranslational translocation
During cotranslational translocation, the Sec61 channel partners with the signal recognition particle (SRP), the signal recognition particle receptor (SR), and the ribosomes to transport the nascent polypeptide chain...
Sec61 channel partners for cotranslational translocation
During cotranslational translocation, the Sec61 channel partners with the signal recognition particle (SRP), the signal recognition particle receptor (SR), and the ribosomes to transport the nascent polypeptide chain...
Post-translational Translocation of Proteins to the RER
A sizable fraction of proteins destined for ER are first synthesized in the cell cytosol and then transported across the ER membrane–a process called post-translational translocation. Similar to cotranslationally translocated proteins, these proteins also use the Sec translocon complex to enter the ER lumen.
Targeting proteins to the ER
Hsp40 and Hsp70 chaperone molecules bind the translated proteins in the cytosol to prevent their folding. The chaperone binding helps to keep the signal...
Targeting proteins to the ER
Hsp40 and Hsp70 chaperone molecules bind the translated proteins in the cytosol to prevent their folding. The chaperone binding helps to keep the signal...
Initiation of Translation
Initiating translation is complex because it involves multiple molecules. Initiator tRNA, ribosomal subunits, and eukaryotic initiation factors (eIFs) are all required to assemble on the initiation codon of mRNA. This process consists of several steps that are mediated by different eIFs.
First, the initiator tRNA must be selected from the pool of elongator tRNAs by eukaryotic initiation factor 2 (eIF2). The initiator tRNA (Met-tRNAi) has conserved sequence elements including modified bases at...
First, the initiator tRNA must be selected from the pool of elongator tRNAs by eukaryotic initiation factor 2 (eIF2). The initiator tRNA (Met-tRNAi) has conserved sequence elements including modified bases at...
Translation in Prokaryotes
Prokaryote translation is a complex, highly coordinated process that converts genetic information from mRNA into functional proteins. It involves three stages: initiation, elongation, and termination, each facilitated by specific molecular components.Initiation of TranslationThe process begins with the assembly of the ribosomal subunits and initiation factors on the mRNA. In bacteria, the 30S ribosomal subunit recognizes the Shine-Dalgarno sequence in the mRNA, a conserved region upstream of...

